This invention relates to air, gas and liquid quality and, more particularly, to devices, apparatus and instruments for airborne (gas) particle and/or liquid contamination quantity counting and particle size measuring by light (laser) beam.
The methods and devices for determining quantity and size of the particles and/or liquid (water) contaminations are now well known, and it is also well known that powerful light or laser and detecting system can be, and have been used to achieve particle size and particle quantity measurements. Such devices, mostly using or computers, are well known and described, for example, in the articles: R. G. Knollenberg, B. Schusterxe2x80x94xe2x80x9cDetection and Sizing of Small Particles in Open Cavity Gas Laser,xe2x80x9d Applied Optics, Vo. 11, No. 7, November 1972, pp. 1515-1520; R. G. Knollenbergxe2x80x94xe2x80x9cAn Active Scattering Aerosol Spectrometer,xe2x80x9d Atmospheric Technology, No. 2, June 1973, pp. 80-81; Schehl, Ergun, Headrickxe2x80x94xe2x80x9cSize Spectrometry of Aerosols Using Light Scattering from the Cavity of a Gas Laser,xe2x80x9d Review of Scientific Instruments, Vol. 44, No. 9, September 1973; R. G. Knollenbergxe2x80x94xe2x80x9cActive Scattering Aerosol Spectrometry,xe2x80x9d National Bureau of Standards Special Publication, No. 412, October 1974, pp. 57-64; R. G. Knollenberg, R. E. Luehrxe2x80x94xe2x80x9cOpen Cavity Laser Active Scattering Particle Spectrometry from 0.05 to 5.0 Microns,xe2x80x9d Fine Particles, Aerosol Generation Measurement, Sampling and Analysis, Academic Press, May 1975, pp. 669-696; R. G. Knollenbergxe2x80x94xe2x80x9cThree New Instruments for Cloud Physics Measurements: The 2-D Spectrometer, the Forward Scattering Spectrometer Probe, and the Active Scattering Aerosol Spectrometer,xe2x80x9d American Meteorological Society, International Conference on Cloud Physics, July 1976, pp. 554-561; R. G. Knollenbergxe2x80x94xe2x80x9cThe Use of Low Power Laser in Particle Size Spectrometryxe2x80x9d, Proceeding of the Society of Photo-Optical Instrumentation Engineers, Practical Applications of Low Power Lasers, Vo. 92, August 1976, pp. 137-152; Eltermanxe2x80x94xe2x80x9cBrewster Angle Light Trap,xe2x80x9d Applied Optics, Vol. 16, No. 9, September 1977; Marplexe2x80x94xe2x80x9cThe Aerodynamics Size Calibration of Optical Particle Counters by Inertial Impactors,xe2x80x9d Aerosol Measurement, 1979; Diehl, Smith, Sydorxe2x80x94xe2x80x9cAnalysis by Suspended Solids by Single-Particle Scattering,xe2x80x9d Applied Optics, Vol. 18, No. 10, May 1979; K. Sudaxe2x80x94Review of Scientific Instruments, Vol. 51, No. 8, August 1980, pp. 1049-1058; R. G. Knollenbergxe2x80x94xe2x80x9cThe Measurement of Particle Sizes Below 0.1 Micrometersxe2x80x9d, Journal of Environment Science, January-February, 1985, pp. 64-67; Petersxe2x80x94xe2x80x9c20 Good Reasons to Use In Situ Particle Monitorsxe2x80x9d, Semiconductor International, Nov. 1992, pp. 52-57 and Busselman et al.xe2x80x94xe2x80x9cIn Situ Particle Monitoring in a Single Wafer Poly Silicon and Silicon Nitride Etch Systemxe2x80x9d, IEEE/SEMI Int""l Semiconductor Manufacturing Science Symposium, 1993, pp. 20-26.
The reference in these articles is made to the devices and methods of particle measurement, utilizing an open cavity laser for particle detection.
The known devices, having the particle detecting means are based on the scattered light collection, as it is mentioned, for example, in U.S. Pat. No. 4,140,395, U.S. Pat. No. 4,798,465, U.S. Pat. No. 5,467,189 and in 5,515,164 of the prior art.
For example, in U.S. Pat. No. 4,140,395 and in U.S. Pat. No. 4,798,465 of the prior art are used the imaging systems, which are based on lenses.
Yet in other prior art (for example, such as U.S. Pat. No. 5,467,189 and U.S. Pat. No. 5,515,164) we can find the devices (sensors) with ellipsoidal mirrors instead of the lens systems or non-divergent quadric mirrors.
All these devices, mentioned in the prior art above, use light scattering focalizing methods. Such methods are based on the collection of the scattered light. A light scattering occurs at the first focal point (focus) by intersecting. Considering stochastic processes of the light scattering, the devices, mentioned in the above prior art, use mirrors or optics. This is necessary for scattered light, collecting and focalizing at the second focal point (focus), where a light detector is placed and intended for scattered light detection.
Further the devices, based on scattered light collection and some other detection methods (for example, by light splitting), use a different variations of the comparison method for the particle size measuring. Such method can be illustrated (see FIG. 1), for example, by U.S. Pat. No. 4,798,465. On FIG. 1 is shown the particle size detection device, using one of the particle measuring comparison method variations. The signal from detectors 1 via the amplifiers 61 follow to the comparators 62, which is connected to the reference voltage means 63. The amplified detected signals are compared with the predetermined reference voltages for the particle size qualifying.
Such methods cannot provide light the sufficiently light the sensitivity related to the increasing requirements to the particle counting and measuring devices, because of the analog (amplitude) method of comparison.
Another and also important deficiency of all known particle analyzing devices is the use of the wire leads (cable) for the particle detecting means connection to the data processing means.
The devices, using the wire (cable) connection of the particle detecting, means to the data processing and control system, are presented by two styles of their configuration: a portable configuration of the particle analyzing device, which is an entire unit comprising particle detecting means (sensor) connected by short wires (short cable) to the microprocessor means, or a remote sensor configuration of the particle analyzing device, wherein, for example, the sensor and the data processing means are represented by two separated and remote of each other units connected by long wires (long cable).
On FIG. 2 is shown, for example, a device (see U.S. Pat. No. 5,524,129) with the wire (cable) connection 20 of the sensor 22 with the microprocessor (CPU) 24(12).
It is known, that all wire (cable) connections in electronic apparatus are a source of the electromagnetic noise, which can create a distortion of the signals. Also the portable devices require local operation with them and exactly in the place of the airborne particle or liquid (water) contaminations assaying. The devices with long cable connection between the remote sensor and the data processing means have a limited mobility, because of cable.
Other known devices by U.S. Pat. Nos. 4,160,246 and 5,751,424 intended for the smoke detection and liquid mixture, gas or solid medium analysis respectively. The smoke detector by U.S. Pat. No. 4,160,246 does not provide the counting and measuring of the particles in the specimen and uses the analog processing of the signals. The probe by U.S. Pat. No. 5,751,424 does not provide the analysis of the airborne particle. Also these devices use one-way wireless communication for the data transmission only and do not provide the wireless transmission of the control commands/signals (automatic modes of turn-on/turn-off, switching of the particle size counting scale, etc.), requiring the handle control of the remote unit.
For example, it is known, that integrated circuits (chips) and semiconductors have been produced in xe2x80x9cclean roomsxe2x80x9d. The air in such xe2x80x9cclean roomsxe2x80x9d should be very well cleaned. The continuing tendencies of improvement in circuit integration and degree of microminiaturization require corresponding improvements of the environment in xe2x80x9cclean roomsxe2x80x9d and efficiency and sensitivity of the measuring devices. And now, as it is known, the sensitivity of the counting and measuring devices should be at least as small as 0.1 xcexcm (Micron). Such rate requires minimum distortions in the data processing signals. Also the measurements should be done in the different places of the semiconductor production areas of xe2x80x9cclean roomsxe2x80x9d and sometimes in the areas, which could be difficult to approach. The same is regarding the pharmaceutical and biological industries, where is required the well condition of the environment.
Thus, the comparison method of the particle size measuring (an analog comparison of the detected signal amplitudes with the appropriate reference voltages) and the wire (cable) connections between the sensors (particle detecting means) and create an insufficient signal to noise ratio, thereby limiting the sensitivity and efficiency of the particle counting and measuring devices. Also such wire (cable) connection, using in the known particle counting and measuring devices with the known devices with the remote sensors, limits the mobility of the particle counting and measuring instruments. Another known system by U.S. Pat. No. 4,160,246, intended for the smoke detection, comprises an infrared radiation source, photodetector, the frequency filters, audio amplifiers, annunciator driver, a plurality of light-emitting diodes (LED) and a horn or buzzer. This device uses a wireless communication (from the smoke detector/transmitter to the receiver/annunciator). Such smoke detector system does not provide counting and measuring of the particles in the specimen Also the device by U.S. Pat. No. 4,160,246 provides the analog processing of the signals.
Accordingly, several objects and advantages of the present invention are to provide an improved methods and apparatus for airborne (gas) particle and/or liquid (water) contamination analysis.
It is the object of the invention to provide an improved method and apparatus for increasing the sensitivity of the particle counting and measuring means.
It is another object of the invention to provide an improved methods and apparatus for increasing the efficiency of the analyzing processes and means.
It is yet another object of the invention to provide an improved method and apparatus for decreasing electromagnetic noises by the elimination of wire (cable) connection between particle detecting means (sensors) and data processing means.
It is still further an object of the invention to provide an improved method and apparatus for increasing the authenticity of the information about air or liquid (water) composition.
It is still another object of the invention to provide an improved method and apparatus for increasing the mobility, compactness and convenient placement possibility of the remote detecting means.
Still, further objects and advantages will become apparent from a consideration of the ensuing description accompanying drawings.